Peter Hansen wrote: > Larry Bates wrote: > >> I'm trying to get the results of binascii.crc32 >> to match the results of another utility that produces >> 32 bit unsigned CRCs. > > > What other utility? As Tim says, there are many CRC32s... the > background notes on this one happen to stumble out at the top of the > list in response to googling for "zip file crc32 checksum polynomial", > though I'm sure there are easier ways. The binascii docs say its CRC32 > is compatible with the Zip file checksum, but they don't describe it > further. > > Generally CRCs are described in terms of their "polynomial", though just > quoting that isn't sufficient to describe their behaviour, but if you > happen to know the polynomial for your utility, someone else can > probably point you to a more appropriate routine, or perhaps explain > what you were doing wrong if the binascii one is actually the right one.. > > -Peter >
Check out the unit test in the following. http://sourceforge.net/projects/crcmod/ I went to a lot of trouble to get the results to match the results of binascii.crc32. As you will see, there are a couple of extra operations even after you get the polynomial and bit ordering correct. Ray -- http://mail.python.org/mailman/listinfo/python-list
